Linux commands

An A-Z Index of the Linux BASH command line

alias    Create an alias
awk      Find and Replace text within file(s)

break    Exit from a loop
builtin  Run a shell builtin

cal      Display a calendar
case     Conditionally perform a command
cat Display the contents of a file cd Change Directory
chgrp Change group ownership
chmod Change access permissions
chown Change file owner and group chroot Run a command with a different root directory
cksum Print CRC checksum and byte counts clear Clear terminal screen cmp Compare two files comm Compare two sorted files line by line command Run a command - ignoring shell functions continue Resume the next iteration of a loop
cp Copy one or more files to another location
cron Daemon to execute scheduled commands crontab Schedule a command to run at a later time
csplit Split a file into context-determined pieces cut Divide a file into several parts date Display or change the date & time dc Desk Calculator dd Data Dump - Convert and copy a file declare Declare variables and give them attributes
df Display free disk space
diff Display the differences between two files
diff3 Show differences among three files
dir Briefly list directory contents dircolors Colour setup for `ls'
dirname Convert a full pathname to just a path dirs Display list of remembered directories du Estimate file space usage echo Display message on screen ed A line-oriented text editor (edlin) egrep Search file(s) for lines that match an extended expression eject Eject CD-ROM enable Enable and disable builtin shell commands env Display, set, or remove environment variables eval Evaluate several commands/arguments exec Execute a command exit Exit the shell expand Convert tabs to spaces export Set an environment variable expr Evaluate expressions factor Print prime factors false Do nothing, unsuccessfully fdformat Low-level format a floppy disk fdisk Partition table manipulator for Linux fgrep Search file(s) for lines that match a fixed string find Search for files that meet a desired criteria fmt Reformat paragraph text fold Wrap text to fit a specified width. for Expand words, and execute commands format Format disks or tapes free Display memory usage fsck Filesystem consistency check and repair. function Define Function Macros gawk Find and Replace text within file(s) getopts Parse positional parameters grep Search file(s) for lines that match a given pattern groups Print group names a user is in gzip Compress or decompress named file(s) hash Remember the full pathname of a name argument head Output the first part of file(s)
history Command History hostname Print or set system name id Print user and group id's if Conditionally perform a command import Capture an X server screen and save the image to file info Help info install Copy files and set attributes join Join lines on a common field kill Stop a process from running less Display output one screen at a time let Perform arithmetic on shell variables ln Make links between files local Create variables locate Find files logname Print current login name logout Exit a login shell lpc Line printer control program lpr Off line print lprint Print a file lprintd Abort a print job lprintq List the print queue lprm Remove jobs from the print queue ls List information about file(s) m4 Macro processor man Help manual mkdir Create new folder(s) mkfifo Make FIFOs (named pipes) mknod Make block or character special files more Display output one screen at a time mount Mount a file system mtools Manipulate MS-DOS files mv Move or rename files or directories nice Set the priority of a command or job nl Number lines and write files nohup Run a command immune to hangups passwd Modify a user password paste Merge lines of files pathchk Check file name portability popd Restore the previous value of the current directory pr Convert text files for printing printcap Printer capability database printenv Print environment variables printf Format and print data ps Process status pushd Save and then change the current directory pwd Print Working Directory quota Display disk usage and limits quotacheck Scan a file system for disk usage quotactl Set disk quotas ram ram disk device rcp Copy files between two machines. read read a line from standard input readonly Mark variables/functions as readonly remsync Synchronize remote files via email return Exit a shell function rm Remove files rmdir Remove folder(s) rpm Remote Package Manager rsync Remote file copy (Synchronize file trees) screen Terminal window manager sdiff Merge two files interactively sed Stream Editor select Accept keyboard input seq Print numeric sequences set Manipulate shell variables and functions shift Shift positional parameters shopt Shell Options shutdown Shutdown or restart linux sleep Delay for a specified time sort Sort text files source Run commands from a file `.' split Split a file into fixed-size pieces su Substitute user identity sum Print a checksum for a file symlink Make a new name for a file sync Synchronize data on disk with memory tac Concatenate and write files in reverse tail Output the last part of files tar Tape ARchiver tee Redirect output to multiple files test Evaluate a conditional expression time Measure Program Resource Use times User and system times touch Change file timestamps top List processes running on the system traceroute Trace Route to Host trap Run a command when a signal is set(bourne) tr Translate, squeeze, and/or delete characters true Do nothing, successfully tsort Topological sort tty Print filename of terminal on stdin type Describe a command ulimit Limit user resources umask Users file creation mask umount Unmount a device unalias Remove an alias uname Print system information unexpand Convert spaces to tabs uniq Uniquify files units Convert units from one scale to another unset Remove variable or function names unshar Unpack shell archive scripts until Execute commands (until error) useradd Create new user account usermod Modify user account users List users currently logged in uuencode Encode a binary file
uudecode Decode a file created by uuencode v Verbosely list directory contents (`ls -l -b') vdir Verbosely list directory contents (`ls -l -b') watch Execute/display a program periodically wc Print byte, word, and line counts whereis Report all known instances of a command which Locate a program file in the user's path. while Execute commands who Print all usernames currently logged in whoami Print the current user id and name (`id -un') xargs Execute utility, passing constructed argument list(s) yes Print a string until interrupted .period Run commands from a file ### Comment / Remark